Deforming tool and process for manufacture

ABSTRACT

In the deformation of geometrically similar components of a component family, in which the characteristic which differs is in particular thickness, there is according to conventional construction techniques of deformation tools a separate deformation tool necessary for each component. The inventive deformation tool system, including the following tool active parts stamp, blank holder and matrix, were in at least one work tool active part is shaped in a mask technique, enable the deformation of various components with this deformation tool system, in that for at least one tool active part at least two exchangeable masks of different characteristics are provided. Depending upon the component of a component family to be produced an optimal mask is selected from the pre-constituted supply of masks and used for deformation of the component in the deformation tool.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention concerns a deformation tool system, a process for manufacture of a deformation tool and a process for manufacture of components of a component family.

2. Description of Related Art

The fundamental sequence of events in the deformation of workpieces comprises introducing the workpiece into a shape-imparting deforming tool, which is comprised of a lower and an upper tool, and applying an external force upon the deformation tool and/or the work piece, which can bring about a flow of the material of the workpiece and its plastic deformation into a shape predetermined by the shape of the tools. Particularly in the deformation of sheets, and depending upon whether a single- or double-acting press is used, the lower or the upper tool is comprised of a tool effective stamp and a blank holder, and the complementary upper or lower tool is comprised of the work tool effective matrix.

In the deformation of geometrically similar components within a component family, which the characteristic difference between family members is in particular the thickness, in accordance with conventional manufacturing processes a separate deformation tool is required for each component. Typical applications can be found in the automobile industry with regard to frame and/or structural parts of the car body manufacture.

Known from the state of the art (DE 25 48 815 A1, DE 16 27 738 A1) are deformation tools in the masking technique and processes for their manufacture. Herein these deformation tools comprise a lower and/or upper tool, which includes a shape imparting shell, that is, a mask, and a support-providing backing material. The shape imparting shell represents in this type of tool construction the shape-determining functional surface of the respective tool for the deformation of a components, while the supporting backing material provides, as the base body, stability of the respective tool. As a manufacturing process for a tool construction of this type, it is described in DE 25 48 815 A1, that the shape determining shells are generated on separate negative models of the respective shape-determining surface, for example via application processes such as hot thermal spraying, and the thus obtained shape providing shells are back-filled thereafter, for example by a casting processes. Disadvantageous in this type of tool manufacturing process is however that the final geometry of both the shape producing shell as well as the backfill is not precisely defined, whereby the reproducibility of the individual components, that is, the shape determining shell and the backfill, is not possible. A further manufacturing process is described in DE 16 27 738 A1, in which the shape producing shell of sheet metal is deformed on a negative model by means of explosion deformation and subsequently backfilled with concrete or a plastic material. Both mentioned processes have the disadvantage, that the production of the backfill material and the presence of the shape producing shell are bonded, and the possibility of a change-out of the shape producing shell, as necessitated for example by a strong friction wear of the shape producing shell, is not possible due to the type of joining of shape producing shell and backfill.

Further it is known from DE 198 07 404 A1 a deforming tool in the mask technique and a process for manufacture thereof, wherein the mask and the backfill exhibit a defined geometry and dimension. It is described therein that the final thickness of the latter mask of the lower and/or upper tool must be taken into consideration already at the front end in the production of the base body of the active parts of the deforming tool. Accordingly a tool of this type is suitable essentially for deformation of a single component and a further, geometrically similar component, which differs from the original component, would require an additional, new deformation tool.

It is the task of the invention to solve the above-mentioned problems, in particular with regard to the reproducibility and exchangeability of masks and the applicability of tool parts to more than one component, and to provide a deformation tool system for the deformation of components, in particular the series manufacture, which exhibits a greater flexibility and at the same time an economical series production, as well as a process for manufacturing a deformation tool and a process for manufacturing a component from a component family of similar geometry.

SUMMARY OF THE INVENTION

With regard to the deformation tool system to be provided, the process for manufacture of a deformation tool and the process for production of components of a component family are set forth in the independent patent claims. The further claims contain advantageous embodiments and further developments of the inventive deformation tool system (Patent claims 2 through 6).

The task with regard to the deformation tool system to be provided is inventively solved thereby, that it includes a lower and an upper tool, where lower and/or upper tool are produced according to the mask technique, and wherein multiple interchangeable masks of different characteristics, in particular with regard to thickness, surface texture and/or thermal conductivity for at least one tool active or effective part of the lower and/or upper tool are provided.

For example, a tool design of this type substantially raises the flexibility of the deformation tool, since the deformation tool enables manufacture of geometrically similar components, which differ from the original component for example in the characteristic of thickness, likewise, in that a certain bandwidth of various component thicknesses is taken into consideration in the manufacture of the base body of the corresponding active part and the corresponding thickness of the new component is, in the end, simply accommodated by means of the exchangeable masks.

A further advantage of the inventive deformation tool system is that the base body of the tool active part can be described precisely by computer controlled data models and therewith can be produced reproducibly independently of the masks by conventional milling processes or also by more modern rapid tooling processes, in particular a rapid tooling technology layer building up process known as laminated object manufacturing (LOM) in which metal layers can be employed, whereby a sufficient stability of the tool is achieved for series production and simultaneously expense and time in the manufacture are saved.

Also advantageous in the inventive deformation tool system is that masks with the same or different characteristics can be produced reproducibly in that they are produced directly with the geometrically exactly defined base body of the tool active part of the deformation tool system in a deformation process or however by separate deforming processes, such as incremental deformation or however for example temperature control deformation processes for non-metallic materials, such as for example carbon fiber composite reinforced materials. Therewith masks of the same or different characteristics can be pre-staged for the deformation tool system in sufficient numbers, whereby the flexibility of the deformation system to deform components of similar geometry of a component family is realized, and beyond this laborious and costly repairs and interruption of a conventional deformation tooling is substantially reduced by a deformation tool system of the present type thereby that the friction wear due to contact between deformation tool and component occurs in the exchangeable masks and that these masks, to the extent that they are worn, can be simply exchanged against a corresponding mask from the pre-staged supply of masks of the deformation tool system.

Alternatively or additionally the task of the deformation system to be provided is inventively solved thereby, that it includes a lower and upper tool, wherein lower and/or upper tool are produced according to the masking technique and wherein for at least two active parts of the lower and upper tool respectively at least one mask of different characteristics, in particular in regard to thickness, surface texture and/or thermal conductivity, are provided.

For example, a work tool arrangement of this type substantially increases the flexibility of the deformation tool, since the deformation tool enables, in the case of a change of the component material or the coating of the component material, for example associated with a change in the tribologic relationship between deformation tool and component and higher heat development or input in the deformation process, by the selection of masks which are suitable and differ in their characteristics for the respective active parts, for example surface texturing and thermal conductivity of the deformation tool, appropriate to the new constraints or conditions.

DETAILED DESCRIPTION OF THE INVENTION

In a advantageous embodiment of the deformation system the temperature development in the tool during the deformation process, and therewith the heating of the deformation tool and the stability of the deformation process, can be controlled thereby, that materials are employed for the masks which, depending upon their thermal conductivity, insulate the deformation tool or supply to it a targeted heating from the deformation process. An increased heat development in the deformation process is to be expected in particular in the deformation of the materials with a tensile strength of greater than 600/nm². Advantageous herein are mask materials, which exhibit at room temperature a thermal conductivity in the range of less than 400 W/mK, preferably the thermal conductivity of the mask materials lies in the range of 15W/mK to 55W/mK.

For reduction of friction and friction wear between deformation tool and component, the surface of the respective mask as the tool part which is in direct contact with the component is to be provided advantageously with a texturing. This preferably occurs by an electronic process, in particular electrical discharged texturing (EDT).

In a further advantageous embodiment of the inventive deformation tool system, the masks are provided as shape-determining shells of cold rolled steel sheet with a thickness of 0.5 mm to 5 mm. Preferably, the thickness of the material to be employed lies in the range of between 1 mm to 2.5 mm, since this material thickness range covers the range of changes occurring in the component thickness of geometrically similar components or components of a component family. Cold-rolled steel sheets as mask materials offer a very good deformability and good friction wear resistance for series production. However, the deformation tool system is not limited to the use of cold rolled steel sheets as mask material, but rather includes all ferrous and non-ferrous metals as well as non-metallic materials and composites and sandwich materials, in particular in conjunction with carbon fiber reinforced composite materials.

In a further preferred embodiment of the deformation tool system, the fixing or bonding of the mask onto a tool active part occurs with use of securing elements on a surface of the work tool active part other than the shape imparting surface. This has the advantage, that it is ensured, that the movement of the component material during deformation does not extend beyond the location of the fixation of the mask to the corresponding backfill material. An influencing of the quality of the component by, for example, scratching or imprinting by the fixing element of the mask is therewith precluded.

The task with regard to the process to be provided for production of a deformation tool, including a tool active dye or punch or punching tool or stamp, a blank holder and a matrix with at least one tool active part according to the masking technique, is inventively solved by that at least one tool active part is joined to a mask which is selected from a supply of at least two exchangeable masks with different characteristics, in particular their thickness, their surface texture and their thermal conductivity.

The advantage of the inventive process for production of a deformation tool lies therein, that in contrast to the previously known state of the art according to DE 25 48 815 A1 and DE 16 27 738 A1, both the backfill material as well as the mask as shape imparting shell are provided precisely as a three-dimensional data set and therewith are reproducible, and that in contrast to DE 198 07 404 A1 the deformation tool cannot be used for only a single component, but rather multiple components of a component family of similar geometry.

The flexibility of the inventive process for production of a deformation tool with regard to the deformation of components of a component family is achieved thereby, that the thickness of multiple components of a component family is already taken into consideration in the construction of the deformation tool and therewith is maintained in the deformation tool. Accordingly not only the thickness of one single component is taken into consideration in the description of backfill material and mask as three dimensional data set, but rather as starting point the maximum thickness of a component is used, and the 3D-data set of the backfill material is constructed based thereupon. By the pre-staging of masks of different characteristics, in particular their thickness, their surface texture and their thermal conductivity, the flexibility of the tool is ensured and, by an employment of suitable masks in the deformation tool, components of a component family can be produced with the deformation tool.

In one advantageous embodiment of the inventive process the backfill material of at least one active part of the deformation tool is produced by the layer building up rapid tooling technology known as laminated object manufacturing (LOM) in conjunction with metal layers. This embodiment is suited to save time and costs in the manufacture of backfill.

Alternatively or additionally the task with regard to the process for manufacture of a deformation tool, including work tool active punch, blank holder and matrix with at least one tool active part in accordance with the mask technique, is inventively solved thereby, that for at least two active parts respectively one mask is employed, which differs in at least one characteristic, in particular thickness, surface texturing and thermal conductivity, from at least the other masks employed in the deformation tool system.

An advantageous embodiment of this type of a process for manufacture of a deformation tool for production of components of a component family of similar geometry ensures that by the manufacturing and pre-staging of masks of different characteristic for at least two active parts of the deformation tool the flexibility of a deformation tool is further substantially increased. Thereby, it is enabled to targetedly influence for example different friction and wear protective characteristics of the upper and lower tool, by for example an change of the component material or a coating of the component material and/or to influence for example heat introduction into the lower and/or upper tool as advantageous for the process control.

The task with regard to the process to be provided for production of components of a component family of similar geometry by deformation by means of a deformation tool, including a tool active part stamp, blank holder and matrix, is inventively solved thereby, that for at least one tool active part a mask optimized for this component is selected from a supply including at least two exchangeable masks with different characteristics, in particular their thickness, their surface texture and their thermal conductivity, and that these are joined with the tool active part.

The advantage of the inventive process for manufacture of components of a component family of similar geometry lies therein, that the process of the deformation of multiple components of a component family of similar geometry is made possible with only one deformation tool.

The flexibility of the inventive process for manufacture of a component of a component family of similar geometry is achieved thereby, that the thickness of multiple components of a component family are already taken into consideration in the construction of the deformation tool and thus included in the deformation tool. Thus not only the thickness of one component is taken into consideration in the description of back feed and mask as three dimensional data set, but rather the maximal thickness of a component of a component family of similar geometry is used as starting point and the 3D-dataset of the backfill is constructed with reference thereto. By the pre-staging of masks of different characteristics, in particular the thickness, their surface texturing and their thermal conductivity, the flexibility of the tool is then ensured, and by the employment of corresponding masks in the deformation tool the varied components of a component family can be produced with the deformation tool.

In an advantageous embodiment of the inventive process for manufacture of a component of a component family of similar geometry, the backfill of at least one active part of the deformation tool a layer is formed using building-up rapid tooling technology known as laminated object manufacturing (LOM) in conjunction with metal layers. This embodiment is suited to save time and expense in the manufacturing of the backfill.

Alternatively or additionally, the task of providing a process for manufacture of a component of a component family of similar geometry by deformation by means of a deformation tool including a tool active stamp, blank holder and matrix, is inventively solved thereby, that for at least two tool active parts respectively one mask optimal for this component is selected, which differs in its characteristics, in particular its thickness, its surface texturing and the thermal conductivity, and is joined to the tool active part.

One such advantageous embodiment of the inventive process ensures that by the production and supply of masks differing in their characteristics for at least two tool active parts of the deformation tool the flexibility of a deformation tool is further substantially increased. Thereby it is made possible to influence in a targeted manner for example different friction and wear conditions of the upper and lower tool, brought about for example by a change of the component material or a coating of the component material, and/or for example a thermal input into the lower and/or upper tool advantageous for process control.

In the following the inventive deformation system and the inventive process for manufacture of a deformation tool and for production of components of a component family of similar geometry is described in greater detail on the basis of an illustrative example:

Beginning with the data set of the component construction, which exists as a rule in the form of a surface data set, a 3D-volumetric model of the deformation tool is constructed. For this the surface data set from the component construction is defined as reference surface in the deformation tool as shape producing surface of the upper tool, in this case the form producing surface of the mask of the tool active part matrix. Beginning therewith, by offset generation both in the one as well as the other normal direction of the reference surface, the 3D outer surface of the tool active part of the deformation tool, that is the stamp, the blank holder and the matrix, is formed. Since components of a component family of similar geometry with component thicknesses of 1 mm, 1.5 mm and 2 mm and with various materials such as DC05 and DP800 are deformed, in the direction of the upper tool an offset of 1 mm of the 3D surface of the tool active part matrix is computed. In the direction of the deformation tool, in order to cover the maximal component thickness, an offset of 3 mm of the 3D-surface of the tool active part stamp and blank holder is arrived at. This manner of preceding enables, by use of a 1 mm thick mask for the tool active part matrix in the upper part and by use of a respectively 1 mm thick mask for the tool active part stamp and blank holder in the lower tool, the production of a component with 2 mm thickness. Analogously thereto, by use of respectively 1.5 mm or 2 mm thick mask for the tool active part stamp and blank holder in the lower tool, the production of 1.5 mm or 1 mm thick component can be made possible. Since the reference surface in the deformation tool with the 3D-surface of the 1 mm thick mask of the tool active part matrix in the upper tool remains unchanged in all cases, the exact component geometry remains, according to the construction data set of the component, the same for all components to be produced of the component family.

Beginning with the thus produced 3D-surface data sets of the tool active parts, the 3D-volumetric models of the backfill to be produced for the respective tool active parts is constructed. The resulting data are processed in a commercially available rapid tooling unit for laminated object manufacturing and, with employment of metal layers, a backfill for individual tool active parts is built up. For increasing the stability of the layer joining and for improved positioning of the individual mechanical layers the stacking of the individual layers occurs by pull anchors and positioning rods. These are subsequently secured with securing elements such as, for example, threaded screws.

The production of the masks occurs according to the processes known according to the state of the art, in particular according DE 198 07 474 A1. The manufacturing process of masks for individual tool active parts, which is in part very labor intensive, is here optimized for the deformation tool system in the manner, that all required masks can be produced in a single work process with differing characteristics, in particular the thickness, the surface texturing and the thermal conductivity. From this there results, in comparison to the multiple conventional tools, advantages with regard to the manufacturing time and the expense of the masks.

In this manner the masks required for the production of components of a component family in thicknesses of 1 mm, 1.5 mm and 2 mm for the tool active part of the deforming tool, are produced directly with the aid of the backfill already produced by the metal-LOM-process of the work tool active part in one deformation process. In this manner then individually all of the masks necessary for the deformation of all components of a component family in all thicknesses, in different materials or in different materials with different surface texturing, are deformed. Subsequently there occurs in certain cases also a final processing of individual masks and the masks are prepared for receiving fixing elements, which ensure the fixing of a mask upon an appropriate backfill, for example they are provided with through-holes for receiving a counter-sunk screw head and for this a flange area is recessed. In the present case the produced masks are fixed outside of the form producing surface on the side surfaces of the backfill with hexagonal screws.

Finally, other masks with different characteristics, in particular surface texturing, are produced. These are produced in separate manufacturing processes parallel to the manufacturing of the backfill and the previously described process of mask production. This is possible because a 3D-data set exists from the tool construction describing precisely the individual masks. For example, carbon-fiber composite masks are produced in different thicknesses and with different surface characteristics. Their manufacture occurs in a conventional manufacturing process for carbon-fiber composite components. Therewith geometric distinct individual carbon-fiber masks are available as soon as the deformation tool is ready for series production.

The thus produced supply of masks of different characteristics, in particular thickness, material and surface texturing, enables the manufacture of all components of the component family of similar geometry with one deformation tool system and with optimal process conditions with respect to friction and wear or for example the thermal input in individual work tool active parts.

Supplementally, by the deformation tool system the repair and maintenance of a deformation tool is kept to a minimum in that, in the case of wear, essentially one mask needs to be changed out. This substantially reduces the required extensive time and associated costs for maintenance, servicing and repair of deformation tools.

The inventive deformation tool system, the inventive process for its manufacture and the inventive process for production of components of a component family of similar geometry has demonstrated itself in the illustrative embodiment of the above described example as particularly suited for sheet metal processing in the automobile industry, in particular deep drawing. Beyond this, it is advantageous that the invention is applicable to both prototype manufacture as well as in the series production. In particular, substantial advantages can be achieved therewith with regard to the flexibility of the deformation tool for deforming of more than only one component, for reduction of costs and time of manufacturing of deformation tools.

The invention is not limited to the above described illustrative embodiment, but rather can be broadly applied.

So it can be useful, for example, in consideration of the extreme friction and wear conditions in the deformation process, to harden or temper the individual masks by a thermal treatment process or to apply in a separate process additional friction and wear reducing surface layers such as, for example, a TiC/TiN-layer.

In another embodiment it may be necessary that backfill materials of individual tool active parts must be produced of a solid material such as for example cast steel materials, by milling processes, for reasons of, for example, the tool geometry or the loads in the deformation process. 

1. A deformation tool system, including the following tool active parts: stamp, blank holder and matrix, wherein at least one tool active part is shaped by a mask technique, wherein, for at least one work tool active part, at least two interchangeable masks of different characteristics, in particular thickness, surface texturing and/or thermal conductivity, are provided and/or wherein for at least two tool active parts respectively at least one mask of different characteristics, in particular thickness, surface texturing and/or thermal conductivity, is provided.
 2. The deformation tool system according to claim 1, wherein the masks are preferably of cold rolled steel sheet in a thickness of 0.5 mm to 5 mm, in particular from 1 to 2.5 mm, and/or the surface of one of the tool active parts and/or one of the masks has a friction and wear reducing texture, which in particular is formed by an electric discharge texturing (EDT) process, and/or the thermal conductivity of a mask material at room temperature is preferably in the range of less than 400 W/mK, in particular from 15 to 55 W/mK.
 3. The deformation tool system according to claim 1, wherein the masks are comprised of composite or sandwich materials, in particular sandwich materials and/or metal sheets in combination with cotton fiber composite materials.
 4. The deformation tool system according to claim 1, wherein the masks are comprised of different mask materials.
 5. The deformation tool system according to claim 1, wherein one mask is fixed on a tool active part using securing elements on a surface different from the shape producing surface of the work tool active part.
 6. The deformation tool system according to claim 1, wherein one of the tool active parts is provided, which is produced using the rapid tooling technique known as metal laminated object manufacturing (metal-LOM).
 7. A process for production of a deformation tool, including the following tool active parts: stamp, blank holder and matrix, wherein at least one tool active part is shaped in a masking technique, wherein at least one tool active part is joined to to one mask, which is selected from a reservoir or a supply of at least two interchangeable masks with different characteristics, in particular with regard to their thickness, their surface texturing and/or thermal conductivity, and/or wherein at least two tool active parts are joined respectively to one mask, which exhibits different characteristics, in particular thickness, surface texturing and/or thermal conductivity.
 8. A process for production of a component of a component family of similar geometry by deforming at least one deformation tool, including the work tool active parts: stamp, blank holder and matrix, wherein for at least one work tool active part a mask optimized for this component is selected from a supply of at least two interchangeable masks with different characteristics, in particular thickness, surface texturing and thermal conductivity and joined with the tool active part and/or wherein for at least two tool active parts respectively one mask optimized for this component is selected, which differ in their characteristics, in particular their thickness, surface texturing and thermal conductivity, and are joined with the work tool active part. 